The present invention relates generally to a method and apparatus for measuring performance of an optical element, and more particularly to an exposure apparatus mounted with a measuring apparatus that measures a wave front aberration of a target optical system, such as a projection optical system that transfers a mask pattern onto an object, and an exposure method and device manufacturing method using the measuring apparatus.
A projection exposure apparatus is used to transfer a pattern on a mask (or a reticle) onto an object to be exposed in manufacturing devices, such as semiconductor devices, e.g., an IC and a LSI, image pickup devices, such as a CCD, display devices, such as a liquid crystal panel, and magnetic heads, in the photolithography process. This exposure apparatus is required to transfer the pattern on the reticle onto the object precisely at a predetermined magnification. For this purpose, it is important to use a projection optical system having good imaging performance and reduced aberration. In particular, due to the recent demands for finer processing to the semiconductor devices, a transferred pattern is more sensitive to the aberration of the optical system. Therefore, there is a demand to measure the optical performance, such as a wave front aberration, of the projection optical system with high precision. In addition, the simple, rapid and inexpensive measurements are important for improved productivity and economical efficiency.
A conventional method that actually exposes a mask pattern onto a wafer, and observes and inspects the resist image using a scanning electron microscope (“SEM”) or another means has a problem in a long time inspection due to the exposure and development, difficult SEM operations, and bad inspection reproducibility due to errors caused by resist applications and developments. Accordingly, as a solution for these problems, various measuring apparatuses have conventionally been proposed, such as a point diffraction interferometer (“PDI”) that has a pinhole used to form an ideal spherical wave, a shearing interferometer, such as a lateral shearing interferometer (“LSI”), or a Talbo interferometer that utilizes the shearing interferometry, and a line diffraction interferometry (“LDI”) that has a slit used to form an ideal cylindrical wave or an ideal elliptical wave. See, for example, Japanese Patent Applications, Publication Nos. 57-64139, 2000-146705, and 2000-97666.
However, the conventional measuring apparatuses still enlarge and increase the cost of the entire system that includes the measuring apparatus and exposure apparatus, and cause a long measuring time.